Power mechanism



Oct. 12 1926.

F. F. DORSEY POWER MECHANISM Filed SeptA 26, 1924 mv@ mmf:

Patented @en 12, 1926..

A STATES PATENT i OFFICE.

FABNUM F. DOR'SEY, 0F ROCHESTER, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, T NORTH EAST APPLIANCES, INC., 0F ROCHESTER, NEW YORK, A COR-4 POILATION 0F NEW YORK.

Bowan. MEcHANrsM.

applicano; mea septembe 2e, 192,4. serial m. 740,127.

thrown into operative engagement with the l roller by means of a spring-pressed device7 when released by the operation of the key, while the motion of the cam has been arrested and controlled by a positively acting escapenient mechanism controlled by the key.

The object of the present invention is to produce mechanism, of the kind in question,

in which the operation shall be rendered positive, particularly with respect to the rotation of the cam to throw it into operation. For this purpose the mechanism is so arranged that the depression of the key i causes a positive rotation to be imparted to the cam, while the cam is arrested and is held in its normal, inactive position by a spring-controlled member.

Other features of the invention will be set forth in connection with the following description of the illustrated embodiment thereof. A

In th'eaccompanying drawings, Fig. 1 is a side-elevation of power mechanism embodying the-present invention, together with certain parts of a typewriter in which the mechanism is used. Fi 2 is a side-elevation, kon an enlarged scae, showing particularly the cam-lever, with the cam and other parts mounted thereon. Fig. 3 is a sectional' view on -the line 3-3 in Fig. 2, looking downwardly.

The invention is illustrated as embodied in a typewriter of a well-known design, comprising type-bars 5, pivoted on a rod 6 and co-operating with a platenw7. Each type-bar is connected, by a pull-rod 8, with a link 9,V the links being pivoted on a rod 10. 'A4 spring 11, attached to each rod 8 acts vto restore the parts to normal position after the operation of the type-bar. The drawings show only a single unit of the machine, comprising a type-bar and the cam-mechanism for actuating this bar. It will be understood, however, that 'each type-bar is provided with a similar cam-mechanism, and that other functions of the machine, such as back-spacing, caseshifting etc., may be performed by cammechanism of the same construction.

.The power-roller 12 is preferably covered with rubber, or some other suitable frictional material, and is rotated constantly by any suitable source of power. The cam 13 has two similarconvex lobes and makes a halfrotation at each operation. It is serrated on its periphery, to prevent slippage against the roller. The cam turns about a pivot 14 mounted in the cam-lever. This lever is formed of two parallel sheet-metal members 15, and the pivot 14 is ixedat its ends in these members. A second pivot 16, fixed in the lever members, turns in a bearing 17 mounted on'Y a Icross-bar 18 on the frame of the typewriter. The horizontal arm 19 of the cam is connected, by a pullrod 20, with the link 9. v

Two pins 21 project from the side of the cam and are engaged by the edge of a sheetmetal arm 22. This spring-arm is fixed to a hub 23 which turns loosely upon a pivot 25.

A spring 27 coiled around the hub 23 engages, at one end, a lug 26 extended from the spring-arm 22, while its other end engages a lug 28 on the cam-lever. This spring acts to press the spring-arm constantly against the pins 21, `and in the normal position of the parts both pins engage the lever, as shown in the drawings, and the cam is thus held accurately in its inactive position.

The cam is thrown intofopcration through the action of' mechanism including two arms 29 and 30, which are ixed to the pivot 25 near its ends. The arm 30 is integral with an arm 31 which has a horizontal lug 32 at its upper end. This lug is embraced by the slotted lower end of an arm 33 depending from a key-lever 34. The key-lever is pivotally mounted at 35, and carries the usual key 36. A spring 37 holds the key-lever normally in raised position.

A pivot-pin 38 is fixed to the lower ends of the arms 29 and 30, and a hub 39 turns loosely upon this pin. A sheet-metal pawl y p The reduced ends of the pivot turn loosely in the sides of the cam-lever.

is liXed to one end of the hub, and is provided with a laterally bent lug 41 which overhangs the edge of the arm 29. A. spring 42, coiled around the hub and engaging the pawl 40 and the arm 30 respectively at its ends, tends to swing the pawl downwardly and to hold it in the position shown, in which the lug 41 limits its downward movement by engagement with the arm 29.

The end of the pawl rests just behind the pin 21 which is in the upper position. When the key 36 is depressed the key-lever swings the arms 29 and 30 tothe right, thus causing the pawl to push against the pin 21 and partially rotate the cam. The form of. the cam is such that this partial rotation brings it into engagement with the power-roller, whereupon the roller rotates the cam and thus swings the cam-lever and actuates the type-bar throughthe connections described. The half-rotation of the cam is completed hy the action of the spring-lever 22 against the lower one of the pins 21, and this rotation is finally arrested when the upper one of the pins comes into engagement with the spring-arm.

' It will be apparent that the force with which the rotation of the cam is initiated is limited only bythe force supplied to the key 36, so that the operation of the cam may be positively started regardless of accidental friction in the mechanism, such as might defeat the operation of a mechanism depending upon spring-action to set the parts in motion.

The invention claimed is:

1. Power mechanism comprising: a constantly driven power-roller; a cam-lever; a Cam journalled thereon and formed to move the lever when rolling in Contact with the power-roller; yielding means for resisting rotation of the cam and holding it in a normal inactive position, out of engagement with the roller; and key-operated means for imparting a positive partial rotation to the cam against the opposition of said yielding means to bring it into rolling engagement with the roller.

2. Power-mechanism comprising: a constantly driven power-roller; a cam-lever; a cam journalled on the cam-lever and provided with a. lateral abutment; an arm pivotally mounted on the cam-lever; a pawl pivoted to said arm and arranged to co-operate with said abutment; and a key connected with said arm and arranged to swing the arm in a direction to cause the pawl to push the abutment and partially rotate the cam to cause it to engage the power-roller.

3. Power-mechanism comprising: a con stantly driven power-roller; a cam-lever; a cam journalled on the cam-lever and provided with two lateral abutments on opposite sides of its axis of rotation; a springpressed member adapted to engage said abl1t ments simultaneously and to retain the cam yieldingly in a normal position out of engagement with the power-roller; and keyoperated means for imparting positively a partial rotation to the cam to cause it to engage the power-roller.

4. Power-mechanism comprising: a constantly driven power-roller; a cam-lever; a cam journalled on the cam-lever and provided with two dianietrically opposite abutments; a spring-pressedarm arranged to engage said abutments to control movement of the cam; a pawl-arm pvotally mounted on the cam-lever; a spring-pressed awl carried by the pawl-arm and adapte to press against one of the abutments when the pawlarm is swung about its pivot; and a key connected with the pawl-arm to actuate the latter.

FARNUM F. DORSEY. 

